The present invention relates to a novel headlamp for an automobile which is capable of forming a clear horizontal cutline and of forming a light-distribution pattern of light which is diffused widely in the horizontal direction.
Among automobile headlamps, the basic arrangement of an auxiliary headlamp (a fog lamp or the like) for an automobile is such that a coil-like filament is disposed in the vicinity of the focus of a reflector having the shape of a paraboloid-of-revolution, in such a manner as to extend along the optical axis of the reflector (so-called C-8 type filament arrangement), and a front lens )laving diffusing lens steps is disposed in front of the reflector, so as to control the light-distribution.
Namely, light-distribution control is made to obtain a specified light-distribution pattern having a horizontal cutline by diffusing the projection pattern of the filament due to the reflector into the horizontal direction through the diffusing lens steps of the front lens.
As another arrangement of an auxiliary headlamp for an automobile, one is known in which a coil-like filament is disposed in the vicinity of the focus of a reflector having the shape of a paraboloid-of-revolution, in such a manner as to orthogonally intersect the optical axis of the reflector (so-called C-6 type filament arrangement), and a front lens having diffusing lens steps is disposed in front of the reflector, so as to control the light distribution.
However, a projection pattern obtained by the reflector has a horizontally inverted 8-shape in this arrangement, and, in this state, it is impossible to obtain a light-distribution pattern which conforms to standards. For this reason, light-distribution control is made to obtain a specified light-distribution pattern having a horizontal cutline by diffusing the projection pattern due to the reflector into the horizontal direction through the diffusing lens steps of the front lens.
With the conventional auxiliary headlamp for an automobile, there are problems in that the cutline becomes unclear due to a control limit of the diffusing lens steps, which play a principal role in the light-distribution control, i.e., since the cutline is formed as an upper edge portion of the projection pattern obtained from the reflector, is forcibly made horizontal by the diffusing lens steps, it is difficult to form a clear cutline without resorting to the aid of a shade disposed below the filament, and in that the light oriented toward the upper side of the horizontal line constitutes dazzling light for an oncoming vehicle. In addition, there is a problem in that it is difficult to obtain a pattern in which the light is diffused widely in the horizontal direction.